1. Technical Field
The present invention relates to a safety cap with a child-resistant function which has a devised cap structure that makes it difficult for infants etc. to carelessly open the cap.
2. Description of the Related Art
There is known a safety cap with a child-resistant function which includes an inner cap with a female screw to be mounted on a mouth of a container, an outer cap that is movable in an axial direction relative to the inner cap, and which incorporates a ratchet mechanism between the inner cap and the outer cap (see, for example, JP 4844807 B1).
The safety cap of JP 4844807 has a plurality of upward ratchet teeth formed on an outer circumference of an upper part of the inner cap and a plurality of downward ratchet pawls formed on a ceiling surface of the outer cap. The ratchet pawls on the outer cap side have a simple flat plate shape. The ratchet teeth on the inner cap side are formed such that their surfaces that make contact with the ratchet pawls on the outer cap side when the safety cap is rotated in a direction in which the safety cap is tightened on the container are perpendicular to main surfaces of the ratchet pawls and such that their surfaces that make contact with the ratchet pawls on the outer cap side when the safety cap is rotated in a direction in which the safety cap is taken off from the container are inclined.
When the outer cap is rotated in the direction in which the safety cap is tightened on the container, the ratchet pawls having a flat plate shape are engaged with the perpendicular surfaces of the ratchet teeth so as to rotate the inner cap together. This allows the female screw of the inner cap to be tightened on a male screw of the container. Meanwhile, when the outer cap is just rotated in the direction in which the safety cap is taken off from the container, the outer cap just spins as the ratchet pawls slip on the inclined surfaces of the ratchet teeth. It is therefore possible to prevent the safety cap from being carelessly taken off. It is necessary to rotate the outer cap while pressing down the outer cap in order to take off the safety cap from the container. JP 4844807 describes that infants are incapable of executing such an operation correctly, and therefore a child-resistant function can be realized (paragraph 0004).